Answer to Question #259041 in Python for Jauani

Question

You are required to implement a simple symbolic equation solver. The equation must be stored in a binary tree.

Each operand or operator should be stored as a tuple of the form (TYPE, VALUE).

For example: (OPERAND, 5), (OPERAND, 7), (OPERATOR, '*’').

Following operators should be supported: addition (+), subtraction (-), multiplication (*), and exponentiation .

Skeleton of this lab is given belo. Complete the bodies of the insert, and evaluate methods. Include your solution in the sections

*Input*

root = Node(('OPERAND', 1))

root = root.insert(('OPERATOR', '+'), False)

root = root.insert(('OPERAND', 2), False)

root = root.insert(('OPERATOR', '*'), True)

root = root.insert(('OPERAND', 3), False)

root = root.insert(('OPERATOR', '+'), False)

root = root.insert(('OPERAND', 3), False)

root = root.insert(('OPERATOR', '^'), False)

root = root.insert(('OPERAND', 2), False)

root.get_output()

*Expected output* = 100

Answer 1

class Tree:
    def __init__(self, node=None):
        self.queue = []
        if node:
            self.queue.append(node)
        self.globalflag = False

    def eval_node(self, node):
        if node.is_leaf:
            return float(node.value)
        elif node.value == '+':
            return self.eval_node(node.left) + self.eval_node(node.right)
        elif node.value == '-':
            return self.eval_node(node.left) - self.eval_node(node.right)
        elif node.value == '*':
            return self.eval_node(node.left) * self.eval_node(node.right)
        elif node.value == '^':
            return self.eval_node(node.left) ** self.eval_node(node.right)

    def process_queue(self):
        while len(self.queue) > 1:
            self.queue[1].left = self.queue[0]
            self.queue[1].right = self.queue[2]
            self.queue.pop(2)
            self.queue.pop(0)

    def get_output(self):
        if len(self.queue) > 1:
            self.process_queue()
        print(self.eval_node(self.queue[0]))

    def insert(self, data, flag):
        if self.globalflag:
            self.queue[-1].right = Node(data)
            self.queue[-1].left = self.queue.pop(-2)
            self.globalflag = False
        else:
            self.globalflag = flag
            self.queue.append(Node(data))
        return self


class Node:
    def __init__(self, data, left=None, right=None):
        self.is_leaf = data[0] == 'OPERAND'
        self.value = data[1]
        self.left = left
        self.right = right

    def __repr__(self):
        return f'(value: {self.value}, left: {self.left}, right: {self.right})'


root = Tree(Node(('OPERAND', 1)))
root = root.insert(('OPERATOR', '+'), False)
root = root.insert(('OPERAND', 2), False)
root = root.insert(('OPERATOR', '*'), True)
root = root.insert(('OPERAND', 3), False)
root = root.insert(('OPERATOR', '+'), False)
root = root.insert(('OPERAND', 3), False)
root = root.insert(('OPERATOR', '^'), False)
root = root.insert(('OPERAND', 2), False)
root.get_output()